1. Field of Invention
This invention relates generally to recycling processes, methods and associated apparatus.
More particularly, the invention relates to processes, methods and apparatus for recycling used and scrap asphalt shingles and shingle-like materials typically comprising an asphalt-saturated felt or fiberglass sheet or other fibrous material with a granular coating.
2. Description of Prior Art
A substantial quantity of used and scrap asphalt shingle material is generated each year from the replacement of shingle roofing, and from the manufacture of new shingles. This shingle material generally consists of irregular to full-sized used or scrap xe2x80x9ctear-offxe2x80x9d shingles removed from roofs, and irregular trim edges, end scraps, cut-out tabs and other scrap and waste from new shingle production. Manufacture of conventional sized shingles typically results in three to six scrap cut-out tabs of approximately xc2xc inch wide by 5 inches long per shingle. It has been estimated that this manufacturing scrap material alone will result in approximately 270,000 tons of waste during the year 2000. Substantially all of this used and scrap shingle material is disposed in land fills, with some portion being disposed through other techniques.
As is well-known, overuse and disposal of waste in landfills has created numerous problems, resulting in the need to transport waste to remote locations in certain areas of the country. Advantages of reducing the disposal of this waste material are well-known, and include conservation of resources, and reducing land fill use. These advantages have resulted in substantial efforts to reclaim and recycle as many materials as economically possible; such recycling efforts being publicly subsidized in certain instances. Therefore, it is desirable to develop new and improved methods and apparatus for recycling used and manufacturing scrap asphalt shingle materials into useful products.
Numerous prior methods for recycling shingle material are known. However, for a variety of reasons, these prior methods have not been widely accepted. In general, prior methods for recycling asphalt shingle material have focused on only limited uses and/or are directed toward only a few specific types of products, resulting in associated limited markets being available for distribution of such products. None of the prior methods provide recycled products suitable for offering in the consumer market. Thus, there is a need for new and improved recycling methods that are suitable for producing a wide variety of products, including consumer related products, from used and manufacturing scrap asphalt shingle material; the manufacture and use of such additional products from recycled shingle material assisting in the reduction of disposal of such used and manufacturing waste material.
Basic molding of articles from asphalt shingle material is disclosed in, for example: Ford, U.S. Pat. No. 1,290,954 discloses chilling asphalt-saturated felt roofing waste product for ease of breaking and grinding the product into small particles, and then forming articles by placing the ground product into a mold under pressure and a small amount of heat. Robinson, U.S. Pat. No. 1,732,281 discloses a machine that shears and agitates asphalt roofing material; the process raising the temperature of the mixture such that the output is a xe2x80x9cplastic mass . . . suitable for molding operations.xe2x80x9d
Much of the prior art related to or including recycling of asphalt shingle material is directed toward road building or road repair. For example: McGovern, U.S. Pat. No. 3,261,269 and Defregger et al. U.S. Pat. No. 3,615,804 disclose methods for preparation of a liquid or semi-liquid product suitable for use in road patching. Glynn, Jr. U.S. Pat. No. 5,344,485 discloses a method for recycling asphalt shingle material in the production of asphaltic concrete blocks. Pavelek, U.S. Pat. No. 5,511,899 discloses the use of loose asphalt shingle tear-off pieces to form a cushioning layer under a road. Richards, U.S. Pat. Nos. 5,221,702 and 5,367,007 disclose methods for the production of road paving blocks molded from a composite material of asphalt, polyethylene, mono-filament fiber, and elastomer; noting that the use of an elastomer for binding and a polymer for strength is a common prior approach for preparation of a product with a composite including recycled asphalt shingle material.
Several other factors have resulted in difficulties with recycling asphalt shingle material on a successful commercial basis. In addition to the limited products and uses for prior recycling art, these factors include: (1) Although there are a few locations of concentrated sources of supply at manufacturing sites, the bulk of the supply of used or scrap shingle material is literally scattered through out the country, as shingles are removed from roofs, with no particularly concentrations of available material except to the extent of concentrations of population; and (2) Persons or businesses are typically interested in recycling used and/or manufacturing scrap asphalt shingle materials because they have a ready supply of such materials available, and such supplies of shingle material are typically found in locations related specifically to the roofing industry. However, as mentioned above, prior methods for recycling shingle material typically utilize other recycled materials that may not be readily available in the same locations. For example, a steady supply of scrap shingle material may be available from a manufacturing plant, whereas a supply of recyclable elastomer would be available from used tires at a tire recycling center, and a supply of recyclable polyethylene may be available from a conventional recycling center. Unfortunately, the locations or such types of sources of recyclable materials may or may not be located within relative proximity of each other. Therefore, recycling shingle material with typical prior methods requires either transportation of these additional materials to the shingle recycling plant, or the use of new materials in the shingle recycling processes.
Thus, there is a need for new and improved methods for recycling asphalt shingle materials into a variety of useful products that do not require substantial supplies of additional raw or recyclable materials, eliminating or reducing the need to locate, purchase and transport such additional materials to the shingle recycling center; and thus further reducing the cost of products made from recycled shingle materials.
The general objective of the present invention is to provide new and improved methods, processes and apparatus for recycling of used and scrap asphalt shingle materials into a variety of useful products.
A detailed objective is to achieve the foregoing by providing for initial processing of the shingle material into (i) fine material having a relatively high aggregate-to-asphalt ratio and (ii) coarse/flake material, each being suitable for further processing according to certain product manufacturing finishing methods and apparatus.
A more detailed objective is to provide such initial processing methods suitable for (i) adjusting the aggregate-to-asphalt composition ratio of the fine material, and (ii) adjusting the maximum flake size of the coarse material.
Another detailed objective of the invention is to provide new methods and apparatus for producing a variety of usefully shaped, high-strength, high-density, durable products from the fine material flowing from initial processing of the shingle material.
A more detailed objective includes providing methods for decorative and/or functional surface treatments of at least exposed surfaces of the shaped products.
Yet another detailed objective of the present invention is to provide new methods and apparatus for producing a variety of useful landscaping and erosion control products from the flake material produced during initial processing of the shingle material.
Still another objective is to provide new and improved methods for producing a composite board product from the flake material.
These and other objectives and advantages of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.